Advanced

Aggregation and Fibril Structure of AβM01-42 and Aβ1-42

Silvers, Robert; Colvin, Michael T; Frederick, Kendra K.; Jacavone, Angela C; Lindquist, Susan; Linse, Sara LU and Griffin, Robert G (2017) In Biochemistry 56(36). p.4850-4859
Abstract

A mechanistic understanding of Aβ aggregation and high-resolution structures of Aβ fibrils and oligomers are vital to elucidating relevant details of neurodegeneration in Alzheimer's disease, which will facilitate the rational design of diagnostic and therapeutic protocols. The most detailed and reproducible insights into structure and kinetics have been achieved using Aβ peptides produced by recombinant expression, which results in an additional methionine at the N-terminus. While the length of the C-terminus is well established to have a profound impact on the peptide's aggregation propensity, structure, and neurotoxicity, the impact of the N-terminal methionine on the aggregation pathways and structure is unclear. For this reason, we... (More)

A mechanistic understanding of Aβ aggregation and high-resolution structures of Aβ fibrils and oligomers are vital to elucidating relevant details of neurodegeneration in Alzheimer's disease, which will facilitate the rational design of diagnostic and therapeutic protocols. The most detailed and reproducible insights into structure and kinetics have been achieved using Aβ peptides produced by recombinant expression, which results in an additional methionine at the N-terminus. While the length of the C-terminus is well established to have a profound impact on the peptide's aggregation propensity, structure, and neurotoxicity, the impact of the N-terminal methionine on the aggregation pathways and structure is unclear. For this reason, we have developed a protocol to produce recombinant Aβ1-42, sans the N-terminal methionine, using an N-terminal small ubiquitin-like modifier-Aβ1-42 fusion protein in reasonable yield, with which we compared aggregation kinetics with AβM01-42 containing the additional methionine residue. The data revealed that Aβ1-42 and AβM01-42 aggregate with similar rates and by the same mechanism, in which the generation of new aggregates is dominated by secondary nucleation of monomers on the surface of fibrils. We also recorded magic angle spinning nuclear magnetic resonance spectra that demonstrated that excellent spectral resolution is maintained with both AβM01-42 and Aβ1-42 and that the chemical shifts are virtually identical in dipolar recoupling experiments that provide information about rigid residues. Collectively, these results indicate that the structure of the fibril core is unaffected by N-terminal methionine. This is consistent with the recent structures of AβM01-42 in which M0 is located at the terminus of a disordered 14-amino acid N-terminal tail.

(Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Biochemistry
volume
56
issue
36
pages
10 pages
publisher
The American Chemical Society
external identifiers
  • scopus:85029387558
  • wos:000410867600016
ISSN
0006-2960
DOI
10.1021/acs.biochem.7b00729
language
English
LU publication?
yes
id
692d7a84-6e95-4ba6-95b4-a6e20782c5f9
date added to LUP
2017-10-02 10:59:26
date last changed
2018-07-15 04:44:24
@article{692d7a84-6e95-4ba6-95b4-a6e20782c5f9,
  abstract     = {<p>A mechanistic understanding of Aβ aggregation and high-resolution structures of Aβ fibrils and oligomers are vital to elucidating relevant details of neurodegeneration in Alzheimer's disease, which will facilitate the rational design of diagnostic and therapeutic protocols. The most detailed and reproducible insights into structure and kinetics have been achieved using Aβ peptides produced by recombinant expression, which results in an additional methionine at the N-terminus. While the length of the C-terminus is well established to have a profound impact on the peptide's aggregation propensity, structure, and neurotoxicity, the impact of the N-terminal methionine on the aggregation pathways and structure is unclear. For this reason, we have developed a protocol to produce recombinant Aβ<sub>1-42</sub>, sans the N-terminal methionine, using an N-terminal small ubiquitin-like modifier-Aβ<sub>1-42</sub> fusion protein in reasonable yield, with which we compared aggregation kinetics with Aβ<sub>M01-42</sub> containing the additional methionine residue. The data revealed that Aβ<sub>1-42</sub> and Aβ<sub>M01-42</sub> aggregate with similar rates and by the same mechanism, in which the generation of new aggregates is dominated by secondary nucleation of monomers on the surface of fibrils. We also recorded magic angle spinning nuclear magnetic resonance spectra that demonstrated that excellent spectral resolution is maintained with both Aβ<sub>M01-42</sub> and Aβ<sub>1-42</sub> and that the chemical shifts are virtually identical in dipolar recoupling experiments that provide information about rigid residues. Collectively, these results indicate that the structure of the fibril core is unaffected by N-terminal methionine. This is consistent with the recent structures of Aβ<sub>M01-42</sub> in which M0 is located at the terminus of a disordered 14-amino acid N-terminal tail.</p>},
  author       = {Silvers, Robert and Colvin, Michael T and Frederick, Kendra K. and Jacavone, Angela C and Lindquist, Susan and Linse, Sara and Griffin, Robert G},
  issn         = {0006-2960},
  language     = {eng},
  month        = {09},
  number       = {36},
  pages        = {4850--4859},
  publisher    = {The American Chemical Society},
  series       = {Biochemistry},
  title        = {Aggregation and Fibril Structure of Aβ<sub>M01-42</sub> and Aβ<sub>1-42</sub>},
  url          = {http://dx.doi.org/10.1021/acs.biochem.7b00729},
  volume       = {56},
  year         = {2017},
}